I needed to do a small Tk project, and the client wanted a combo-box. After looking at a different module (now no longer available separately), which was poorly documented and which I ran into problems with, I converted to this module.
Tk-JComboBox provides a combobox with a convenient interface and many helper functions. I did not run into bugs, and seems very nice. If you are using Tk and want a combobox, then this module is a life-saver.